The annual mortality rate for all lung diseases is estimated to be approximately 250,000 in the US in 2000. About 150,000 patients were related to acute, potentially reversible respiratory failure and 100,000 patients related to chronic respiratory failure due to chronic obstructive lung disease (COPD) or chronic irreversible respiratory failure due to other illness. The estimated economic burden of these diseases is in the range of 72 billion dollars per year. The rate of death related to COPD has increased by 54%, and the World Health Organization (WHO) estimated that COPD will affect 5-15% of all adults in industrialized countries and accounting for 3 million deaths worldwide in 2020, as the 5th most prevalent disease and the 3rd leading cause of mortality.
The primary purpose of this design is to replace the oxygenation function of the diseased lung with acute or chronic or ventilatory impairment. Because the exchange rate of CO.sub2 by the lungs is about 200 times more than that of oxygen, the oxygenation problem is the first and most serious clinical problem for us to face. This invention is premised upon the fact that most of the clinical problems of CO.sub.2 retention can be resolved simply by the patients themselves without the mechanical ventilation to increase the minute ventilation. Therefore, the Applicants simply focus the design of this invention on the resolutions for the main problem of acute, moderate to severe hypoxemia and chronic respiratory failure with long-term hypoxemia. Due to the ongoing improvement of biomaterial, the possibility of applying normal pressure to hyperbaric nano-sized pure oxygen bubbles to improve oxygenation of the intracaval deoxygenated hemoglobin is attainable. In patients with acute respiratory failure, the normal pressure to hyperbaric intravascular nano-bubbling oxygenator can replace the conventional mechanical ventilator, IVOX (intravascular oxygenator), IMO (intravenous membrane oxygenator), and/or ECMO (extracorporeal membrane oxygenator) to facilitate the oxygen demand of the patients. In patients of chronic respiratory failure, a low-flow intravenous oxygenator can replace conventional oxygen therapy system, improving the power and the motivation of patient activities.                The invention is directed at the intravascular nano-bubbling oxygenator that utilizes an intravascular catheter with numerous nano-porous surface, in order to facilitate the binding of oxygen bubbles with the deoxygenated hemoglobin of red cells in the cardiovascular system. The inventions were designed to Improve the clinical hypoxic patients with any kinds of acute or chronic lung diseases.        
1. Field of Invention
The invention relates artificial to the normal pressure to hyperbaric intravascular nano-bubbling oxygenator, and more particularly to the different design of either one lumen catheter and/or multi lumens catheters with numerous nano-porous surface to facilitate the flow of nano-sized pure oxygen bubbles to the cardiovascular system.
2. Description of Related Arts
The primary purpose of the ventilation is to bring the air into and out the lungs, therefore oxygen can be added into the lungs and carbon dioxide can be removed. The volume of the pulmonary capillary circulation is about 150 ml, spreading over a surface area of approximately 750 square feet. This capillary surface area surrounds 300 million air sacs called alveoli. The deoxygenated venous return is oxygenated in less than one second in the pulmonary circulation due to huge capillary surface and extremely thin blood-alveolar barrier approximately one micrometer in distance. This allows the blood to be replenished with oxygen and for the excess carbon dioxide to be removed.
There have been numerous efforts in the past 40 years to achieve artificial ventilation function, such as negative pressure and positive pressure mechanical ventilator, and extracorporeal membrane oxygenator (ECMO).
Positive-pressure mechanical ventilation is a somewhat efficient and safe means for improving gas exchange in the patients with acute respiratory failure. However, serious adverse effects may occur with prolonged duration of intensive respiratory support or high oxygen fraction. These hazardous effects, including oxygen toxicity, barotraumas, altered hormone and enzyme systems, mechanical ventilation induced lung injury (VILI), disuse atrophy of skeleton muscles, and added to the morbidity and mortality rates for these patients.
Another approach to artificial lung function, extracorporeal membrane oxygenation (ECMO) constitutes a mechanism for prolonged pulmonary bypass, which has been developed and optimized over several decades but has limited clinical utility today as a state-of-the-art artificial lung. The ECMO system Includes an extra-corporeal pump and membrane system that performs a gas transfer across membranes. Despite the numerous advances in the implementation of ECMO over the years, its core technology is unchanged and continues to face important limitations. The limitations of ECMO include the requirement for a large and complex blood pump and oxygenator system, the necessity for a surgical procedure for cannulation, the need for systemic anticoagulation, the labor intensive implementation, the exceeding high cost, and a high rate of complications, including bleeding and infection, protein absorption, and platelet adhesion on the surface of the oxygenator membrane. As a result of these limitations, ECMO has become limited in its utility to select cases of neonatal respiratory failure, where reversibility is considered to be highly likely.                One approach to artificial lung functions has been by gas sparing or diffusion of gas across the membrane surface of hollow fibers placed within the blood supply. Previous efforts have achieved some success, and have taught much to pulmonary physiologists, but gas sparing or diffusion has not yet achieved the degree of gas exchanges optimally desired. The development of the intravascular oxygenator (IVOX) presented a natural extension in the artificial lung art since it was capable of performing intracorporeal gas exchange across an array of hollow fiber membranes situated within the inferior vena cava but did not require any form of blood pump. The insertion of the IVOX effectively introduced a large amount of gas transfer surface area (up to 600 cm.sup.2) without alternation of systemic hemodynamics, unfortunately, as with ECMO, the IVOX system has numerous limitations including a moderate rate of achievable gas exchange, difficulty in device implantation, a relatively high rate of adverse events, and a significant rate of device malfunctions, including blood-to-gas leaks due to broken hollow fibers.        
Clinically, there is still a long way to go for us to achieve perfect artificial oxygenation whether in acute patients or long-term care. Therefore, a serious need exists for new technology and therapeutic approaches that have the potential to provide acute, intermediate to chronic, and long-term respiratory support for patients suffering from severe pulmonary failure. There also remains a paramount need for an efficient and inexpensive technology to achieve sustained oxygen concentration in the blood, thereby bypassing the diseased lung without resorting to further damage.